A space experiment conducted by Italian scientists has for the first time shown that a lack of resistance, that is gravity, activates bone-destroying cells.
An article on the study says that the finding attains significance as it may help better understand why bedridden patients and astronauts experience bone loss.
Published in The FASEB Journal, the article also says that the outcome provides an entirely new drug target for stopping the process.
"This study cuts straight to the bone in terms of why our skeletons deteriorate with disuse," said Dr. Gerald Weissmann, Editor-in-Chief of the journal.
"As is the case with human intelligence, bone loss is an example of 'use it or lose it'. This study from space has pinpointed the cellular culprits that destroy our bones when we don't use them to support weight," Weissmann added.
The researchers used two sets of bone-destroying cells, called "osteoclasts", obtained from the bone marrow of mice femurs.
They launched one set into space via the European Space Agency's 2007 FOTON-M3 mission, and kept the other set on Earth.
On the satellite, the cells were maintained in custom-designed bioreactors equipped with automatic nutrient providers.
At the same time, the other set of cells were kept in the same type of bioreactors on the Earth's surface.
The experiment was stopped after twelve days, and the cells were examined.
The researchers found an increase in genes involved in osteoclast maturation and activity, as well as increased bone loss when compared to the cells on Earth.
"Space might be the final frontier, but we've got some serious hurdles to clear before we conquer microgravity, and bone loss is one of them," Weissmann said.
"Even here on Earth, we all face bone loss. Osteoporosis inexorably hits men and women alike, and this European study points to one cause: lack of resistance," Weissmann added.